Which currrent SP regs are evolutions of which older ones?

[DA Aquamaster]

So when buying used is there any clear way to tell if I have a us model or a foreign model of a reg if the model numbers are the same? Thats the only thing I hate about scubapro is the non standardization between countries.

The G500 is the only second stage that I am awares of where there is any reported differneces in the reg caused by changes made when production moved to Italy. I am not sure why changes were made in the case.

If I remember correctly, the center of the US made G500's purge cover was black while the Italian counterpart's purge cover was grey. Of course, if I remember incorrectly, it could be the other way around.

There are other minor age related differences in some of the secodn stages...

Older D400's had an aspirator incorporating a metal orfice while the late production models used a two piece arrangement with a metal aspirator body with a plastic orifice insert. The older orificed ones are easier to fine tune but with some effort you can get the plastic orificed D400's to perform nearly as well.

G250's vary a lot with age with the earliest being essentially plastic cased Balanced Adjustables with the latest G250 HP's havng plastic airbarrels and new balance chambers and adjustment knobs.

With many old SP second stages it's hard to tell what you will have when you open the case as they are normally readily upgradable and can vary a lot in how much they have been upgraded in the last one to three decades. Adjustables and Balanced Adjustables for example turn up with a variety of poppets depending on if they were converted to BA status, when the conversion occurred and when they were last servcied. In order to use the current S-wing poppet in a BA, the balance chamber and spring are replaced as well as the poppet making this conversion as extensive as converting an Adjustable to balanced status. The good news is that both the poppet and balance chmaber come in the G250/G200B/BA annual service kit and the cost of the new spring is only about $1.00.

 

[84CJ7]

The only reason I ask is especially in the UK online shops certian oddball numbers and models come up.

I was recently told by LDS that the mk 18 I was looking at wasn't good to get here because all the parts are much harder to get since its a non-US reg and so I settled on just the 16, though that swivel and extra HP port sounded nice. Also theres that oddball 380 2nd that I saw in an ebay auction and though was a typo till I found it on the UK sites, is that a another non US or just an older 390 thats still in production other than here? The LDS seemed to imply that there were many current SP regs being sold elsewhere that were different than here and that confused me.